Researchers from McGill University and the University of British
Columbia (UBC) have simulated in the lab the process that can turn
ordinary volcanic eruptions into so-called “supervolcanoes,” with
potentially devastating worldwide impact.

The study was conducted by Dr. Ben Kennedy and and Dr. Mark
Jellinek of UBC’s Department of Earth and Ocean Sciences, and Dr.
John Stix, chair of McGill University’s Department of Earth and
Planetary Sciences. Their results were published May 25 in the
journal Nature Geoscience.

Supervolcanoes are orders of magnitude greater than any volcanic
eruption in historic times. They are capable of causing
long-lasting change to weather, threatening the extinction of
species, and covering huge areas with lava and ash.

Using volcanic models made of plexiglass filled with corn syrup,
the researchers simulated how magma in a volcano’s magma chamber
might behave if the roof of the chamber caved in during an
eruption.

“The magma was being stirred by the roof falling into the magma
chamber,” Stix explained. “This causes lots of complicated flow
effects that are unique to a supervolcano eruption.”

“There is currently no way to predict a supervolcano eruption,”
said Kennedy, a post-doctoral fellow at UBC. “But this new
information explains for the first time what happens inside a magma
chamber as the roof caves in, and provides insights that could be
useful when making hazard maps of such an eruption.”

The eruption of Mount Tambora in Indonesia in 1815 – the only
known supervolcano eruption in modern history – was 10 times more
powerful than Krakatoa and more than 100 times more powerful than
Vesuvius or Mount St. Helens. It caused more than 100,000 deaths in
Indonesia alone, and blew a column of ash about 70 kilometres into
the atmosphere. The resulting disruptions of the planet’s climate
led 1816 to be christened “the year without summer.”

“And this was a small supervolcano,” said Stix. “A really big
one could create the equivalent of a global nuclear winter. There
would be devastation for many hundreds of kilometres near the
eruption and there would be would be global crop failures because
of the ash falling from the sky, and even more important, because
of the rapid cooling of the climate.”

There are potential supervolcano sites all over the world, most
famously under Yellowstone National Park in Wyoming, the setting of
the 2005 BBC/Discovery Channel docudrama Supervolcano,
which imagined an almost-total collapse of the world economy
following an eruption.